Mesenchymal stem cells (MSCs), with high self-renewal ability and multipotency, are commonly used as the seed cells for tissue engineering. However, the reduction and loss of multipotential ability ...after necessary expansion
set up a heavy obstacle to the clinical application of MSCs. Here in this study, we exploit the autologous crystallization ability of biocompatible poly (ε-caprolactone) (PCL) to obtain uniformly distributed nanoneedle arrays. By controlling the molecular weight of PCL, nanoneedle with a width of 2 μm and height of 50 nm, 80 nm, and 100 nm can be successfully fabricated. After surface chemical modification with polydopamine (PDA), the water contact angle of the fabricated PCL nanoneedle arrays are reduced from 84° to almost 60° with no significant change of the nanostructure. All the fabricated substrates are cultured with bone marrow MSCs (BMMSCs), and the adhesion, spreading, proliferation ability and multipotency of cells on different substrates are investigated. Compared with the BMMSCs cultured on pure PCL nanoneedle arrays, the decoration of PDA can improve the adhesion and spreading of cells and further change them from aggregated distribution to laminar distribution. Nevertheless, the laminar distribution of cultured cells leads to a weak cell-cell interaction, and hence the multipotency of BMMSCs cultured on the PCL-PDA substrates is decimated. On the contrary, the pure PCL nanoneedle arrays can be used to maintain the multipotency of BMMSCs
clustered growth, and the PCL1 nanoneedle array with a height of 50 nm is more promising than the other 2 with regard to the highest proliferation rate and best multipotential differentiation ability of cultured cells. Interestingly, there is a positive correlation between the strength of cell-cell interaction and the multipotency of stem cells
. In conclusion, we have successfully maintained the multipotency of BMMSCs by using the PCL nanoneedle arrays, especially the PCL1 nanoneedle array with a height of 50 nm, as the substrates for
extension, and further revealed the importance of cell-cell interaction on the multipotency of MSCs. The study provides a theoretical basis for the behavioral regulation of MSCs, and is instructive to the design of tissue engineering scaffolds.
Lead halide perovskite solar cells (PSCs) with solution processability, low defect concentration, low cost and high output manufacturing have emerged as promising third-generation photovoltaic ...technologies. After an unprecedented speed of development, the power conversion efficiencies of small-area PSCs have exceeded 25%, and meanwhile large-scale perovskite modules are also on a rapid rise. At this stage, considering the significant progress in the fabrication of perovskite films with controllable morphology and crystallinity, it is necessary to conduct reviews on the updated understandings of the nucleation and crystal growth behaviors of perovskites. This review aims to clarify the related mechanisms of the complex perovskite formation process, and is devoted to giving a timely summary of the recent advances. Strategies for controlling perovskite nucleation and crystal growth are also discussed.
This investigation was attempted to introduce carbon nanotubes (CNTs) onto surface of copper powders in order to improve heat transfer performance of copper matrix for engineering application of ...electrical packaging materials. The Ni/MgO catalyst was formed on the copper powders surface by means of codeposition method. CVD technique was executed to fabricate uniform CNTs on copper powders and effect of reaction temperature on the morphology of CNTs was surveyed. The results showed that CNTs products on the copper powder surface were distributed uniformly even if reaction temperature was different. The diameter dimension of CNTs was within the scope of 30~60 nm. Growth behaviors of CNTs by CVD method were considered to be “tip-growth” mechanism. Raman spectra of CNTs proved that intensity ratio of D-band to G-band (ID/IG) increased as deposition reaction temperature increased, which implied that order degree of graphitic structure in synthesized CNTs improved.
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FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, UL, UM, UPUK
Cancer organoids, a three‐dimensional (3D) culture system of cancer cells derived from tumor tissues, recapitulate physiological structure of the parental tumor. Different tumor organoids have been ...established for a variety of tumor types, such as colorectal, liver, stomach, pancreatic and brain tumors. Some tumor organoid biobanks are built to screen and discover novel antitumor drug targets. Moreover, patients‐derived tumor organoids (PDOs) could predict treatment response to chemoradiotherapy, targeted therapy and immunotherapy to provide guidance for personalized cancer therapy. In this review, we provide an updated overview of tumor organoid development, summarize general approach to establish tumor organoids, and discuss the application of anti‐cancer drug screening based on tumor organoid and its application in personalized therapy. We also outline the opportunities and challenges for organoids to guide precision medicine.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Technical debt is a metaphor to reflect the tradeoff software engineers make between short-term benefits and long-term stability. Self-admitted technical debt (SATD), a variant of technical debt, has ...been proposed to identify debt that is
intentionally introduced
during software development, e.g., temporary fixes and workarounds. Previous studies have leveraged human-summarized patterns (which represent n-gram phrases that can be used to identify SATD) or text-mining techniques to detect SATD in source code comments. However, several characteristics of SATD features in code comments, such as vocabulary diversity, project uniqueness, length, and semantic variations, pose a big challenge to the accuracy of pattern or traditional text-mining-based SATD detection, especially for cross-project deployment. Furthermore, although traditional text-mining-based method outperforms pattern-based method in prediction accuracy, the text features it uses are less intuitive than human-summarized patterns, which makes the prediction results hard to explain. To improve the accuracy of SATD prediction, especially for cross-project prediction, we propose a Convolutional Neural Network-- (CNN) based approach for classifying code comments as SATD or non-SATD. To improve the explainability of our model’s prediction results, we exploit the computational structure of CNNs to identify key phrases and patterns in code comments that are most relevant to SATD. We have conducted an extensive set of experiments with 62,566 code comments from 10 open-source projects and a user study with 150 comments of another three projects. Our evaluation confirms the effectiveness of different aspects of our approach and its superior performance, generalizability, adaptability, and explainability over current state-of-the-art traditional text-mining-based methods for SATD classification.
•We introduce the TDHFCVRP-D-VDS and present a bi-objective optimization model.•The flight speed of drones is variable.•HFCVs travel at a time-dependent speed.•We design a non-dominated sorting ...genetic algorithm III with intelligent selection.•Numerous experiments are conducted to derive meaningful managerial insights.
This paper proposes a novel problem called the time-dependent hydrogen fuel cell vehicle routing problem with drones and variable drone speeds (TDHFCVRP-D-VDS). In this problem, a fleet of hydrogen fuel cell vehicles (HFCVs) are equipped with multiple unmanned aerial vehicles (UAVs) to perform delivery and pickup services within the customers’ time windows. The UAV is capable of performing pickup operations after the delivery service, as long as it does not exceed its energy capacity. The HFCV can launch and retrieve the UAV multiple times as needed throughout the routing process. We establish a mixed integer programming model to simultaneously minimize the total cost and makespan, and verify its accuracy by Gurobi. To tackle larger-scale instances, we propose a non-dominated sorting genetic algorithm III with intelligent selection (NSGA-III-IS). The initial population is generated using four distinct approaches aimed at enhancing both diversity and quality. Considering the customers’ time windows, we factor in the temporal-spatial distances between customers when generating the initial population. Our approach employs a two-phase algorithm for developing initial solutions. In the first phase, the algorithm focuses on generating UAV trips, while in the second phase, it creates joint delivery routes for both the HFCV and the UAV. To enhance the optimization process, we have developed four strategies for optimizing UAV speed. These strategies dynamically adjust the UAV’s speed in response to the customers’ time windows and the HFCVs’ arrival times. Additionally, we have integrated an intelligent selection mechanism to optimize the execution probabilities of both general and problem-specific operators. The experimental results demonstrate the following: (1) The proposed NSGA-III-IS outperforms other variant algorithms and two benchmark algorithms; (2) UAVs significantly benefit from variable flight speeds, resulting in reduced costs and improved efficiency; (3) The HFCV with UAV joint delivery pattern is superior for reducing carbon emissions compared to other joint delivery patterns; (4) Longer customer time windows and optimized UAV speed strategies are effective in reducing the total cost, makespan, and total UAV hover waiting time; (5) Finally, a method that combines multi-attribute decision-making with principal component analysis is utilized to aid decision-makers in selecting satisfactory solutions.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The uniform nanocopper film was deposited on the surface of micron β-SiC particle by magnetron sputtering technology successfully. The surface morphology and phase constitution of the β-SiC particle ...with nanocopper film were analyzed and dynamic deposition behavior was investigated in detail. The concept of dynamic deposition was put forward to interpret formation mechanism of copper nanofilm on the surface of β-SiC particles.
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FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, UL, UM, UPUK
beta -cyclodextrin-butane sulfonic acid is reported to be an efficient catalyst for the one-pot synthesis of 1-amidoalkyl-2-naphthols by the multicomponent condensation of aromatic aldehydes, beta ...-naphthol and amides under solvent-free conditions. The present methodology offers several advantages such as shorter reaction time, mild reaction conditions, a simple operational procedure and use of a recyclable catalyst.
Abstract
The engine mount transmission force can be used as an important basis to evaluate the vibration isolation performance of the engine mounting system. However, there is a lack of testing ...equipment and methods for the transmission force. The force sensor and the test method of the transmission force is studied. The finite element model of the mounting element is established to analyze the arrangement position of the sensor. The force sensor is developed based on the resistance strain gauge. The sensor is arranged in the middle of the intermediate bolt. The test system of mount transmission force is established at the same time. The driving force of driving wheel is obtained through the chassis dynamometer test. The force sensor is calibrated base on the test data. The results of mounting transmission force are obtained through the vehicle road test.
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